The present application makes reference to MIL-STD-188-141A Notice 2, which is herein incorporated by reference.
The present invention relates generally to high frequency (HF) communication systems using automatic link establishment (ALE) protocols and waveforms of the type defined in MIL-STD-188-141A Notice 2. More particularly, the present invention relates to an improved ALE waveform and protocol for establishing a link more quickly than has been otherwise possible, while exchanging link quality analysis (LQA) information.
High frequency (HF) radio has traditionally been a medium used to provide economical, long and short distance non-line-of-sight communications. However, establishing communication links on various frequencies between remotely positioned HF radios or stations can be difficult due to the interfering effects of the environment and the terrain. Because changing conditions continuously alter the quality of various communication links, an HF radio operator has historically been required to be very skilled.
Automatic link establishment (ALE) has been available in HF radios for a considerable time. Commonly used ALE methods and protocols facilitating communications between two or more HF radios comply with a protocol described in detail in the military standard document published by the United States Government under the Publication No. MIL-STD-188-141A Notice 2 (hereinafter Notice 2). This document is openly available to the public, with unlimited distribution. In the current algorithms defined by Notice 2, link establishment between HF radios takes longer than is preferred in the HF radio user community. Generally, the user community desires faster linking while still maintaining the Notice 2 feature of interchanging link quality analysis (LQA) information that allows optimization of subsequent voice or digital data exchange. Current Notice 2 compliant systems require approximately 13 seconds of connect time for radios using only three characters in their address. To many in the HF radio community, this is far too long. Users desire a longer address length, but do not like the resulting additional connect times. Also, no standards exist in Notice 2 to allow radios to interact digitally once a link has been established.